   (s/keys :req-un [::type
                    ::color/foreground-color
                    ::color/background-color]))
+
+(s/fdef empty-block
+        :args (s/cat :options (s/keys :opt-un [::color/foreground-color
+                                               ::color/background-color]))
+        :ret ::empty-block)
 
 (s/def ::block (s/or ::text-block 
                      ::empty-block))

                   ::font/style
                   ::text]))

(defn empty-block
  [{:keys [foreground-color
           background-color]

                           ::content]))

(s/fdef terminal
        :args (s/cat :context ::context
                     :terminal-options 
                     (s/keys :req-un [::rows
                                      ::cols
